I wonder looking at your day whether your LO is rather overtired? I think you are counting A time from the start of E, but you really need to count it from eyes open to eyes closed. If we do that, your A times are more like 2.5h, 3-3.5h, 4-4.5h which are super-long. If he's only having short naps you probably need to try to get another one in there, I suspect a lot of his disturbed nights might be to do with tiredness as much as anything else.
I would keep your first nap at about 2.5h A for now, and then bring that second nap right back to more like 2.5h from waking from nap 1. Hopefully that might mean a longer nap, and you'll probably need the 3rd nap too for now. It may be you need (eventually) to push the first A time to get a longer first nap, which will move your second nap later in the day and allow you to drop the 3rd nap properly.
What do you think?